Fronstin said it was the worst such incident at the arena in her 12 years there.

The victims were taken to Jackson Memorial Hospital, seven to the hospital's Ryder Trauma Center.

The victims were all men, ranging in age from 18 to 29, a hospital spokeswoman said. All were treated and released Tuesday night, except for one in serious condition, she said.

According to paramedic reports, the victims had wounds in several places -- one was stabbed in the face, another stabbed in the back, another stabbed in the head.

On stage Tuesday night was R&B singer R. Kelly, joined by rapper NAS and singers Foxy Brown, Kelly Price and Deb Cox. A fight reportedly broke out during the show after 9 p.m., and police surrounded the arena to begin their investigation into what started the fight and how it escalated into the eight assaults.